The problem is the following: The Falcon has a register that can be used to select either 8 MHz or 16 MHz as CPU frequency. Hatari emulates this register, so if TOS or a program writes a value in the register, the emulator switches to 8 or 16 MHz accordingly. Now TOS seems to write to this register during boot, so you always end up in 16 MHz after a reset. I've now changed the code in Hatari a bit to ignore writes to the register if the user selected a frequency > 16 MHz, I hope that should fix the problem: https://hg.tuxfamily.org/mercurialroot/ ... 4adb62da35